Low-carbon upcycling of vanadium slag into doped cathodes for high-performance zinc batteries

Abstract

Developing sustainable aqueous energy storage systems is crucial for advancing renewable energy utilization. Herein, a short-process strategy that integrates vanadium metallurgy and material preparation to synthesize high-performance cathodes is proposed for aqueous zinc batteries. By selectively removing harmful impurities from vanadium-slag leachate while utilizing beneficial impurities as dopants, NH₄⁺-intercalated and metal-doped V₂O₅ (NHVO-M_x) is efficiently synthesized. The resulting material exhibits enhanced Zn²⁺ diffusion kinetics due to its expanded interlayer spacing and low crystallinity structure, while its reduced bandgap significantly accelerates electron transfer. It delivers a high specific capacity of 454.4 mAh g⁻¹ at 0.1 A g⁻¹ and maintains 86.6% capacity retention after 3000 cycles at 8 A g⁻¹. Furthermore, this material is employed in a pouch cell, achieving a capacity exceeding 0.39 Ah. This innovative approach reduces costs by 40% and lowers carbon emissions by over 65% by efficiently utilizing inherent impurities instead of relying on conventional chemical additives. It not only simplifies the purification process but also enhances the battery's capacity and sustainability. This work establishes a green, streamlined synthesis paradigm for next-generation aqueous batteries by converting industrial waste impurities into valuable functional components.